Reaction of Metal Alkoxides with Lysine: Substitution of Alkoxide Ligands vs. Lactam Formation

Summary. Reaction of Ti(OEt)₄ with lysine results in the formation of Ti(OEt)₃(lysinate), as previously reported. Contrary to that, Al(O^sBu)₃ only catalyzes the formation of 3-aminocaprolactam, and no substitution product was observed. The reaction of Zr(OBu)₄ with lysine at room temperature produced both 3-aminocaprolactam and Zr(OBu)₃(lysinate); the lysinate complex was not observed when the reaction was performed at elevated temperatures.Received February 17, 2003; accepted February 21, 2003 Published online June 12, 2003     

On the Coordination Properties of New Bicyclophosphite-Carbohydrates

Summary. The coordination behavior of newly developed bicyclophosphite ligands toward Mo(0), Rh(I), and Pt(II) was studied.Reactions at different ratios of metal to ligand were done. It was found that the ligands act as monodentate ones and form with hexacarbonylmolybdenum(0) complexes with the general formula Mo(CO)₅L by replacing only one carbonyl ligand. Coordination experiments toward acetylacetonatodicarbonylrhodium(I) resulted in the formation of undefined compounds. Toward dichlorocyclooctadienylplatinum(II) the monomeric phosphorus ligands act as monodentate ligands forming complexes of the general structure cis-PtCl₂L₂. All the synthesized platinum-complexes possess cis-configuration (proven by ³¹P NMR). The corresponding coordination compounds were isolated and characterized by elemental analyses and ¹H, ¹³C, and ³¹P NMR.     

Toposelective and Chiroselective Self-Assembly of [2×2] Grid-Type Inorganic Arrays Containing Different Octahedral Metallic Centers

The introduction of different metal ions in specific positions is achieved in the synthesis of [2×2] grid-type heterometallic complexes (see schematic representation; the black bars symbolize the ditopic ligands, and the circles the different metals ions). This novel method for the construction of inorganic architectures opens the way to a number of developments.     

New Polyoxometalates Containing Hybrid Polymers and Their Potential for Nano‐Patterning

Two new polyoxometalate (POM)‐based hybrid monomers (Bu₄N)₅(H)[P₂V₃W₁₅O₅₉{(OCH₂)₃CNHCO(CH₃)C?CH₂}] ( 2 ) and (S(CH₃)₂C₆H₄OCOC(CH₃)=CH₂)₆[PVMo₁₀O₄₀] ( 5 ) were developed by grafting polymerizable organic units covalently or electrostatically onto Wells–Dawson and Keggin‐type clusters and were characterized by analytical and spectroscopic techniques including ESI‐MS and/or single‐crystal X‐ray diffraction analyses. Radical initiated polymerization of 2 and 5 with organic monomers (methacryloyloxy)phenyldimethylsulfonium triflate (MAPDST) and/or methylmethacrylate (MMA) yielded a new series of POM/polymer hybrids that were characterized by ¹H, ³¹P NMR and IR spectroscopic techniques, gel‐permeation chromatography as well as thermal analyses. Preliminary tests were conducted on these POM/polymer hybrids to evaluate their properties as photoresists using electron beam (E‐beam)/extreme ultraviolet (EUV) lithographic techniques. It was observed that the POM/polymer hybrid of 2 with MAPDST exhibited improved sensitivity under EUV lithographic conditions in comparison to the MAPDST homopolymer resist possibly due to the efficient photon harvesting by the POM clusters from the EUV source.     

Synthesis,Crystal Structures,and Thermal Properties of New Zinc(II) Thiocyanato Coordination Compounds

Reaction of zinc(II) thiocyanate with pyrazine, pyrimidine, pyridazine, and pyridine leads to the formation of new zinc(II) thiocyanato coordination compounds. In bis(isothiocyanato‐N)‐bis(μ₂‐pyrazine‐N,N) zinc(II) ( 1 ) and bis(isothiocyanato‐N)‐bis(μ₂‐pyrimidine‐N,N) zinc(II) ( 2 ) the zinc atoms are coordinated by four nitrogen atoms of the diazine ligands and two nitrogen atoms of the isothiocyanato anions within slightly distorted octahedra. The zinc atoms are connected by the diazine ligands into layers, which are further linked by weak intermolecular S ··· S interactions in 1 and by weak intermolecular C–H ··· S hydrogen bonding in 2 . In bis(isothiocyanato‐N)‐bis(pyridazine‐N) ( 3 ) discrete complexes are found, in which the zinc atoms are coordinated by two nitrogen atoms of the isothiocyanato ligands and two nitrogen atoms of the pyridazine ligands. The crystal structure of bis(isothiocyanato‐N)‐tetrakis(pyridine‐N) ( 4 ) is known and consists of discrete complexes, in which the zinc atoms are octahedrally coordinated by two thiocyanato anions and four pyridine molecules. Investigations using simultaneous differential thermoanalysis and thermogravimetry, X‐ray powder diffraction and IR spectroscopy prove that on heating, the ligand‐rich compounds 1 , 2 , and 3 decompose without the formation of ligand‐deficient intermediate phases. In contrast, compound 4 looses the pyridine ligands in two different steps, leading to the formation of the literature known ligand‐deficient compound bis(isothiocyanato‐N)‐bis(pyridine‐N) ( 5 ) as an intermediate. The crystal structure of compound 5 consists of tetrahedrally coordinated zinc atoms which are surrounded by two isothiocyanato anions and two pyridine ligands. The structures and the thermal reactivity are discussed and compared with this of related transition metal isothiocyanates with pyrazine, pyrimidine, pyridazine, and pyridine.     

Novel Inorganic–Organic Hybrid Coordination Polymer [(C10H16N)3(Ag6I9)] n : Synthesis, Structure and Optical Limiting Effect

A novel 1-D organic–inorganic silver(I)-iodide coordination architecture [(C₁₀H₁₆N)₃(Ag₆I₉)] _n (1) (C₁₀H₁₆N⁺=N-butyl-2-methyl-pyridinium) templated by appropriate cation has been constructed and structurally and optically characterized. The inorganic moiety of 1 presents one-dimensional hackle chain arrangement that results from the edges-sharing of AgI₄ tetrahedrons. Static attracting interactions between organic counter cations and inorganic chains are presented and contribute to the crystal packing. The optical limiting experiment shows that the present polymer exhibits a large optical limiting capacity.     

Chemistry in Interphases—A New Approach to Organometallic Syntheses and Catalysis

Combining the advantages of homogeneous and heterogeneous catalysis is still a problem that has not been satisfactorily solved. Chemistry in interphases offers a new approach for overcoming the difficulties, as is described in this article. Owing to the swellable or porous matrix, an interphase represents a state which in the most favorable case is similar to that of a solution. Moreover the proper choice of a mobile hybrid copolymer enables the control of the density and accessibility of the reactive centers, which results in a distinct improvement of the activity of the catalysts (two examples are shown schematically).     

Synthesis and Characterization of Organically Templated Copper Halides with Zero and One-dimensional Hybrid Structures: (nbq)4Cu4I8 and [(ipq)2(Cu5I7)] n

Two new organically templated copper halides, (nbq)₄Cu₄I₈ (1) and [(ipq)₂(Cu₅I₇)] _n (2) have been synthesized in the presence of nbq⁺ and ibq⁺ (nbq⁺ = N-(n-butyl)-quinolinium, ibq⁺ = N-(iso-pentyl)-quinolinium) acting as structure-directing agents(SDAs). Both of the compounds present hybrid structures with SDAs and inorganic moieties being incorporated. In 1, tetrameric Cu₄I₈ ⁴⁻ anion is composed by edge-sharing CuI₄ tetrahedrons and CuI₃ planar triangles. But the inorganic framework of 2 presents one-dimensional arrangement which results from the tetrahedron CuI₄ and pseudo trigonal pyramid CuI₃ through edge-sharing fashion. Electrostatic interactions between organic counter cations and inorganic moieties could be observed and contribute to the crystal packing. Both compounds are further characterized by IR, UV–Vis, elemental analysis, fluorescence and cyclic voltammetry.     

Synthesis, Characterization, and Catalytic Activity of Rh(I) Complexes with (S)-BINAPO, an Axially Chiral Inducer Capable of Hemilabile P,O-Heterobidentate Coordination

Summary.  The reaction of dinuclear rhodium(I) derivatives of the formula [Rh(DIOL)X]₂ with the axially chiral phosphinyl phosphane 2-(diphenylphosphinyl)-2′-(diphenylphosphanyl)-1,1′-binaphthalene ((S)-BINAPO, 1) leads to the formation of cationic complexes [(BINAPO)Rh(DIOL)]⁺ where the ligand (S)-BINAPO consistently displays a P,O-chelate coordination which is mantained even in solvents of fair polarity. The mononuclear rhodium(I) complexes (S)-2-diphenylphosphanyl-2′-diphenylphosphinyl-1,1′-binaphthalene-(1,5-cyclooctadiene) rhodium tetrafluoroborate (3b) and (S)-2-diphenylphosphanyl-2′-diphenylphosphinyl-1,1′-binaphthalene-(1,4-norbornadiene) rhodium tetrafluoroborate (3c) with 1,5-cyclooctadiene (COD) and 2,5-norbornadiene (NBD) as the diolefin were isolated and characterized. Both show a fluxional behaviour in solution which is due to the mobility of the diolefin rather than to a displacement-recombination of the oxygenated arm of the ligand. The mobility of the 1,4-norbornadiene ligand in 3c is extremely pronounced and the coordinated diolefin flexibility could be frozen only at about 200 K. These complexes are active but poorly stereoselective catalysts for the hydrogenation, hydroboration, and hydroformylation of alkenes. Received June 16, 2000. Accepted (revised) July 24, 2000